Alternator issue - 4.2TD Patrol 2006 Hitachi LR1100-705E

[Rip'n'Shred]

Any auto sparkies or DIY'ers that could help out

I have a bit of an issue with my alternator. It's been working fine since I bought the truck in April this year, I have fitted dual battery system and has been working all ok.

Wednesday (2 days ago) I noticed the volt gauge was only reading around 12.5 volts whilst driving home and the second battery wasn't taking charge due to the solenoid not kicking in, ie low voltage cut out.

Checked obvious things, belt ok, fuses ok, etc

Thursday morning it was charging ok, both batteries around 14v. Coming home it was ok too, then suddenly started playing up again. I turned off engine and restarted to drop off second battery and had main battery charging at 14v. I hit the solenoid override button to join batteries together and the charge dropped down to 12v. I watched the volt gauge on the way home and it intermittently changed from around 12v, with very little amps; to 14v pulling around 40amps, to charge both batteries back up I'm assuming (headlights on too).

Spoke to unhelpful auto sparkies today that just wanted to sell me a new alternator for $600!!!!! Gee its been a while since I bought one! :boggle: (no pump on rear either, different model)

I came home and removed my alternator and dismantled it , checked the bearings were ok, brushes appear ok, plenty of travel out with rotor removed and spring tensions seems good, soldered joints of rectifier to stator all appear ok, slip rings ok. All seems ok visually. I cleaned the slip rings with some scotch brite, and reassembled and refitted (had to do school pick ups ). Started up engine and it went straight to 12.3v with very little current (about 3amp I think). I checked battery with multimeter and confirmed volt gauge is accurate, 12.31v. Checked output at alternator, same. After a minute or two I checked again and found 14.1v, lots of current charging battery. Turned off and restarted, 14.1v again. Turned off for 1/2hr and restarted, bloody 12v! :irked:

I've tried searching the internet for info on how to test diodes (rectifier) and regulator with no luck.

I am suspecting the regulator but want to test it to be sure. The alternator gets pretty hot fairly quick too.

Any ideas?????

It is a Hitachi LR1100-705E as fitted genuine to 2006 TD42Ti Nissan Patrol.

Thanks in advance

[Yendor]

In the GQ workshop manual, it goes through how to test the individual components of the alternator, such as the stator, rotor, power and exciter diodes.

Unfortunately you are unable to test the regulator without having specific testing equipment.

Most multimeters have a diode checker built in. When checking the diodes also try gentle pulling on the diode, sometimes they will just fall apart but can test ok with the multimeter.

You might have problems finding a replacement regulator or diode plate if they are faulty, you might be better off getting a replacement alternator. Have you tried Patrolapart?

The other thing to check is the wiring going to the alternator, make sure these circuits are ok and there are no breaks in the wire harness.

[threedogs]

Just Paid $ 380 for genuine alternator, but sure you can get them cheaper, mine is 3lt auto.
No warning no nothing, just overheated and tilt trayed it home
Go 100 amp minimum

[Yendor]

3D you need to turn down the boom box or turn up the hearing aid

Looking at your photo, the colour and shape of that shaft it must of been howling.

For $380 that would of been the Hitachi with the solid pulley not the clutch pulley one.

[Rip'n'Shred]

Thanks to all for advise. I'm thinking stuffed regulator and am hunting around for a replacement, without much luck.

Will try patrolapart. Thanks

[threedogs]

Yendor swear on my sons grave it made no noise at all, All it did was Overheat it took 2 seconds that my mate picked up and that was that.
no noise whats so ever,swear to the Patrol gods, even Mate says absolutely nothing I could have done different, weird as

[Yendor]

Yendor swear on my sons grave it made no noise at all, All it did was Overheat it took 2 seconds that my mate picked up and that was that.
no noise whats so ever,swear to the Patrol gods, even Mate says absolutely nothing I could have done different, weird as

It's just another one of the many quirks of ZD30, sometimes I think the patrol gods look the other way when it comes to this engine.

[Rip'n'Shred]

I found a supplier for a regulator. I'll give it a go. Worth the effort for $76 posted. It's been behaving again lately. Oh the joys of an intermittent fault.

[jimmi]

Alternators dont charge flat out all the time, its a demand thing. if your getting 12.1v-12.5v that is pretty much Battery Voltage only. check your sense line to the alternater, failing that your can trick your to think its running lower than what it is with these, http://cgi.ebay.com.au/ws/eBayISAPI....ht_3356wt_1165.
these boost the voltage 0.5v.